533f9ee332
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This commit allows to synchronise multiple HackRFs with a synchronisation error **below 1 sampling period**
> WARNING: Use this at your own risk. If you don't know what you are doing you may damage your HackRF.
> The author takes no responsability for potential damages
Usage example: synchronise two HackRFs
======================================
1. Chose the master HackRF which will send the synchronisation pulse (HackRF0). HackRF1 will represent the slave hackrf.
2. Retreive the serial number of both HackRFs using `hackrf_info`
3. Use a wire to connect `SYNC_CMD` of HackRF0 to `SYNC_IN` of HackRF0 and HackRF1
4. Run `hackrf_transfer` with the argument `-H 1` to enable hardware synchronisation:
```
$ hackrf_tranfer ... -r rec1.bin -d HackRF1_serial -H 1 | hackrf_transfer ... -r rec0.bin -d HackRF0_serial -H 1
```
rec0.bin and rec1.bin will have a time offset below 1 sampling period.
The 1PPS output of GNSS receivers can be used to synchronise HackRFs even if they are far from each other.
>DON'T APPLY INCOMPATIBLE VOLTAGE LEVELS TO THE CPLD PINS
Signal | Header |Pin | Description
-------|--------|----|------------
`SYNC_IN` | P28 | 16 | Synchronisation pulse input
`SYNC_CMD` | P28 | 15 | Synchronisation pulse output
Note:
=====
I had to remove CPLD-based decimation to use a GPIO for enabling hardware.
More info:
==========
[M. Bartolucci, J. A. Del Peral-Rosado, R. Estatuet-Castillo, J. A. Garcia-Molina, M. Crisci and G. E. Corazza, "Synchronisation of low-cost open source SDRs for navigation applications," 2016 8th ESA Workshop on Satellite Navigation Technologies and European Workshop on GNSS Signals and Signal Processing (NAVITEC), Noordwijk, 2016, pp. 1-7.](http://ieeexplore.ieee.org/document/7849328/)
[Alternative link](http://spcomnav.uab.es/docs/conferences/Bartolucci_NAVITEC_2016.pdf)
61 lines
1.8 KiB
C
61 lines
1.8 KiB
C
/*
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* Copyright 2012 Jared Boone <jared@sharebrained.com>
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*
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* This file is part of HackRF.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; see the file COPYING. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street,
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* Boston, MA 02110-1301, USA.
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*/
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#ifndef __SGPIO_H__
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#define __SGPIO_H__
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#include <stdint.h>
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#include <stdbool.h>
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#include <libopencm3/lpc43xx/sgpio.h>
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#include "gpio.h"
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typedef enum {
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SGPIO_DIRECTION_RX,
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SGPIO_DIRECTION_TX,
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} sgpio_direction_t;
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typedef struct sgpio_config_t {
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gpio_t gpio_rx_q_invert;
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gpio_t gpio_hw_sync_enable;
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bool slice_mode_multislice;
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} sgpio_config_t;
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void sgpio_configure_pin_functions(sgpio_config_t* const config);
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void sgpio_test_interface(sgpio_config_t* const config);
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void sgpio_set_slice_mode(
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sgpio_config_t* const config,
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const bool multi_slice
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);
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void sgpio_configure(
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sgpio_config_t* const config,
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const sgpio_direction_t direction
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);
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void sgpio_cpld_stream_enable(sgpio_config_t* const config);
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void sgpio_cpld_stream_disable(sgpio_config_t* const config);
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bool sgpio_cpld_stream_is_enabled(sgpio_config_t* const config);
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bool sgpio_cpld_stream_rx_set_decimation(sgpio_config_t* const config, const uint_fast8_t n);
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void sgpio_cpld_stream_rx_set_q_invert(sgpio_config_t* const config, const uint_fast8_t invert);
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#endif//__SGPIO_H__
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